Process for producing auxiliary liquids for the polymerization of ethylene



I a 2,919,242 Umted States Patent Off ce v Des his .of mixtures of organometallic compounds, especially aluminum alkyl compounds, with compounds of metals of the 4th to 6th subgroups of the periodic system, espe- '2,919,242 PROCESS Fog rnonncnsc AUXILIARY LIQUIDS cially titanium compounds, and that particularly favor- FOR THE OLYMERIZATION F ETHYLENE able results are obtained if petroleum distiliates in the Hetmut Kolhllg,Dutshllfg'llamhomsahd Nikolaus fi gasoline or diesel oil boiling range are first refined in Ohefhauselbflotteh, Germany, asstgnors to Ruhl'eheme the vapor state and at temperatures between about 400 Akfiengeseuschafi oherhaushn'nolten Getmahy and 600 C. over A1 0 and/ or SiO -containing catalysts N Drawing. Application February 6, 1957 and/ or are passed, with hydrogen or hydrogen-contain- Serial No. 638,448 10 ing gases, over a hydrogenation catalyst and dried, whereupon the distillates, prior to being charged to the poly- Claims Priority, PP Germany February 1956 merization reactor, are mixed with small amounts of the 5 Claims (Ch 0 ,4 catalyst used for the polymerization or its individual cornponents, preferably with titanium tetrachloride, while The polymerization of ethyhme at pressures hetow carefully excluding moisture, and are then separated from about 100 kg./ sq. cm. and at temperatures up to about the PreclPltate h 100 C is known In this process, use ts made f Thus, it is a requirement of the process of the invention alysts which consist of mixtures of organometallic cornthat either a high-temperature refining and a hydrogenapounds, especially alumnium alkyl compounds,with cornor only a hydrogehauon be effected Pnor to the pounds of metals of the 4th to 6th subgroups of the hsrh treatment with small amounts of the catalyst used for Odie system (see Belgian Patents Nos 532,362 and the polymerization. The treatment with thepatalyst re- 534792 ahdttAhgewahdte 67, 541447 (1955)). sults in the separation, among other impurities, of the In this synthesis, use is generally made of an auxiliary last portions of water which cannot be removed by dryhquid in which the polyethylene formed is suspended. ing with conventional drying agents. It is absolutely nec- The auxiliary liquid serves to ensure good agitation of to remove the PYeeiPitate formed in the tfetatmeht the reaction mixture until the synthesis is terminated thus Wlth the he l or lts eompohehtsi e Otherwise h permitting the removal of the heat of reaction. It is ther quantltles of catalyst would he destreyeft y these necessary that the hydrocarbon fractions used as auxdecomposltlon Products of the catalyst or lts p iliar li uid be ver carefully freed from moisture and P dune? the e e ot the Subsequent p lymerizaoxygeneontaining c ompounds since otherwise the course e Increased Yletd t p b yt n O a ned by f polymerization is disturbed. in general, the pohh the working method of the invention involves a reducmerization of ethylene is also impaired by a content of tteh of the heheehteht of the potyethytehe pmductd 1h unsaturated hydrocarbons in the auxiliary liquid. Up to the potymfinzatlon- :rhetefote, a htlmbef of p ra ional the present, fractions of aliphatic hydrocarbons in the Steps Prevtously 'e removing h ash rom t e gasoline or diesel oil boiling range have most widely been raw product can be eh' used as auxiliary liquid. Several processes have already The treatment of the auxlhary hquld Wlth the P 3- been proposed for the preparation and purification of thehzehoh catalysts m m n 15 Preferably fractions of this khttl effected in a vessel with sti rrer at elevated tempera- In many cases, purely aliphatic hydrocarbon fractions 40 three of as htgh as about 100 Werhmght. elevated as obtained, for example, in the Fischer-Tropsch synthetemperature has e advantage h h ,Puntymg effect sis, are not available. Hydrocarbon fractions derived of the eatatyht. or he .eompoheht 1s htghet and h the f Psttoleum frequently consist of mixtures of formed precipitate will settle more readily and its rephatics, naphthenes and aromatics. Fractions of this thevth'wlh be i remevat Aeah be effected by kind cannot be used directly as auxiliary liquids for the Setthhg and/er httretteh; t 9% h htterates may polymerization of ethylene. Especially due to the imt used If 9 9 the auxlharyhqmd should t fi purities contained therein, e.g. the sulfur-containing comteeted to a etsttheheh after separhhoh of the preetpttate' pounds, they cause considerable disturbances in the Moreover has e h h ftvmble to eheet t course of the polymerization. In our copending applicatreatment the auxthary i .wlth the potymenzeheh tion of even date it has been suggested to prepare suitcfltatystPr he eehhpehehts t presence of ethytehe able hydrocarbon mixtures for this purpose from since this results m the formation of a small amount of troleum by first subjecting petroleum-derived distillates polyethylene Whleh as a fitter very good in the gasoline or diesel oil boiling range, in the vapor Suns have h obtthhed by the treatment of the state and at temperatures between 400 and 600 C., to troleumedenved hydrocarbon fractions wlt'h titanium a refining over A1 0 and/ or SiO -containing catalysts, tetraehlonde' subsequently passing them over a hydrogenation catalyst, It i to pteporhoh the qhahhty of the and then drying them. It is also possible to hydrogenate tt e t eathtyst or he .eethpehehts so that the suitable fractions over sulfur-proof catalysts without a than hqmd eohtthhs only aemah excess of these 7 previous high-temperature refining over A1 0 and/or pehhds' Therefore the hydrocarbon mixtures Should SiO -containing catalysts. Particularly good results have have a eohteht of eatatyst or its components of below been obtained, however by combining the two meas gram/liter and preferably below 0.05 gram per liter mesafter the separation of the precipitate formed by the addi- The process of the invention offers the possibility of tion of the Catalyst tts'eempehehts- The q y still further improving the purity of hydrocarbon 'fracqtltred is Preferably determined y a Preceding smahrscate Y tions of this kind and of considerably increasing the yield laboratory test in which the Content of catalyst its of polyethylene based on the quantity of catalyst added. components in the filtrate is determined after the precipi- It has been found that hydrocarbon mixtures can easily tate formed has been separated. be produced from petroleum which are suitable as aux- In the following, the process according to the inveniliary liquids for the polymerization of ethylene effected tion will be more fully described in the example but it at pressures of below 100 kg./ sq. cm. and at temperatures should be understood that this is given by way of illusup to about C. with the use of catalysts consisting tration and not of limitation and that many changes may 3 be made in the details without departing from the spirit ethylene is completed, the following yields of poly- Of the l'llvelltl'ollethylene are obtained:

Example Grams of polyethylene A, distillate ck-j -iy d flpyn A b j Crude, b fi per gram of catalyst tween 80 and 180? C dlh yi d m fi mg 5 Hydrocarbon auxiliary liquid not pretreated with by -Weight-is passedover acatalyst consisting of catalyst 305 Al p t 52; (3, and a rate i p by m f Hydrocarbon auxiliaryliquid treated with catalysL- 545 li id di ill 1 a b volume f camyst r Hydrocarbon auxiliary liquid pretreated with diethyl' hour. The sulfur content of the refinedlproduct amounts aluminum m 9 f 465 to 0.006% by weight. Subsequently, the refined product 10 Hydrocarbon auxiiiaiy i d pretreated with titaniis passed, at a pressureo f ZQ kgQ/sq. cm, in upward dium teiraciliofidfi 594 rection through i an insidediameie-lifli i m: iiiiedi h P T the pretreatment with catalyst by 53% for the pretreatqlckel catalyst s el t i e o ms o ment with diethyl aluminum monochloride, and by 95% iioiii 100 Paris P- i 5 SYQ magiifisia and mo for the pretreatment With titanium tetrachloride. t parts of l i t :selghur. The; reaction temperature is main- What We claim i i i 20.00 ieiiieiice time iii, tile ieaciion l. A process for producing, from petroleum, hydrociiaiiibei' is about i r-t, Thepmduct iiiiis treated is carbonmixturcs to be used as auxiliary liquids for the avi an inside 1??? of 200 fined ith gralluiar about 100 kg./sq. cm and at t mperatures up to about i 5 hours The 51131 li 'Q Obtained has a s'iiiui of aluminum alkyl compounds with titanium tetrachloieiii of 1000795 y weight and 9 of aiomaiic of ride, which comprises first sub ecting said petroleum- The aiiaiyiicai chai'acieiisiics sum as neuiiaiiza derived distillates in the gasoline and diesel oil boiling n n mber, sapouificatiou numb hY rO Y n m range, in the vapor state to a catalytic refining treatment and iodine number are zero. The total oxygen contents jngluding passage, at temperatures between about 400 and fi :9 0003595 as dgiemiiiied wiiii piieiiyi isopio 600 C., over a catalyst selected from the group consist- P Po ing of A1 0 SiO and a mixture thereof, and a passage is theg ggggd L ng; 'z t' g gt gzggggrs o f g gl l'f zl i zg of said distillates together with a hydrogen-containing gas at temperatures between about 150 and 300 C. over a tlge1 gatalylst used for the polymerization and consisting ydmgenan'on catalyst, drying thc fi d and h Ethyl allg; 01f titaliumhtletraich 05:58 223d2 51 2 m f i genated dzstillates, and finally mixing the dlstrllates, prior iii in m iioc on a gram 0 P to hem char edt the ol merizatlonr actor, with small merrzationcatalyst perliter of the hydrocarbon fraction. f, f S a s g f the golymenzanon f l g n flffg ioimeii iiiiei'eiioiiiii atmosphere ethylene, while carefully excluding moisture, and sepai i i ratingthem from the precipitate formed. q g Portion iii-the y r q i is P 2. The process according to claim 1, wherein the polyesse e Saiiie manner with dieiiiyi aiiiminum mono merization catalyst used in the last step of the hydrocarchlorrde 1n a nitrogen atmosphere, adding 0 15 gram of on treatment is titanium tetrachloride diethyiaiummum -l iitel' 0f the hydro 40 3. The process according to claim 1 in which said i carbon iiaciioii- Here i the precipitate formed is treatment of the auxiliary liquid with polymerization catsubsequently separated.

Finally, a third portion of the hydrocarbon fraction is Vessel and in h presence f ethy1ene stirred up in the same manner with 0.15 gram of titanium 4. Th'e'process according to claim 1, in which the tetrachloride per liter of the hydrocarbon fraction and quantity f the polymerization catalyst remammg m the Separated from the p p formed ydrocarbon fraction after it has been separated from Y Way of Fo i one poiymeiizaiioil each is the precipitate formed, is less than 0.1 gram per liter. now eifected with the hydrocarbon fraction purified by The process according to l i 1, i which the refining and hydrogenation iii-id with the iiydmcaibsii quantity of the polymerization catalyst remaining in the fractions siibsequeiiiiy: e d with i poiymeiizaiioii hydrocarbon fraction after it has been separated from the catalyst, methyl-aluminum monochloride and titanium precipitate formed, is less than 0.05 gram per liter.

the hydrocarbon fraction are filled into a stirring vessel References Cit d i the fil of this patent of 5 liters capacity, which had been carefully flushed with highly purified ethylene gas. After heating-up of UNITED STATES PATENTS the hydrocarbon fractionto about 50 C., the catalyst 1,365,235 cross June 2 solution is added while constantly stirring and passing 2,073,973 MuCkeiifiiss i6, 1937 through ethylene. The catalyst solution is prepared by 2,419,029 Obeifeii P i947 mixing together 70 cc. of hydrocarbon fraction, 0.64 2,421,320 e t May i947 gram of diethyl aluminum monochloride and 0.86 gram 2,461,069 Marisic et ai 8, 1949 of titanium tetrachloride and intensively stirring the mix- 2,721,189 Andi/@011 ei ai i955 ture for about 30 minutes. Afiter the addition of the cat- 2,769,753 Huichmgs ai i956 alyst solution, the temperature increases to about 70 C. 2,769,762 Annabie 5i ai 1956 After the first hour of reaction has elapsed, 3 cc. of air 2,771,401 Shepherd i956 carefully freed from moisture and'other disturbing impurities, are added hourly to the inflowing ethylene gas FOREIGN PATENTS stream, within l-2 minutes.- After the conversion of 538,782 Belgium Dec. 6, 1955 

1. A PROCESS FOR PRODUCING, FROM PETROLEUM, HYDROCARBON MIXTURES TO BE USED AS AUXILIARY LIQUIDS FOR THE POLYMERIZATION OF ETHYLENE EFFECTED AT PRESSURES BELOW ABOUT 100 KG./SQ.CM. AND AT TEMPERATURE UP TO ABOUT 100*C. WITH THE USE OF CATLYSTS CONSISTING OF MIXTURES OF ALUMINUM ALKYL COMPOUNDS WITH TITANIUM TETRADHLORIDE, WHICH COMPRISES FIRST SUBJECTING SAID PETROLEUMDERIVED DISTILLATES IN THE GASOLINE AND DIESEL OIL BOILING RANGE, IN THE VAPOR STATE TO A CATALYTIC REFINING TREATMENT INCLUDING PASSAGE, AT TEMPERATURES BETWEEN ABOUT 400 AND 600*C., OVER A CATALYST SELECTED FROM THE GROUP CONSISTING OF AL2O3, SIO2, AND A MIXTURE THEREOF, AND A PASSAGE OF SAID DISTILLATED TOGETHER WITH AHYDROGEN-CONTAINING GAS AT TEMPERATURES BETWEEN ABOUT 150 AND 300*C. OVER A HYDROGENTAION CATALYST, DRYING THE PURIFIED AND HYDROGENATED DISTILLATES, AND FINALLY MIXING THE DISTILLATES, PRIOR TO BEING CHARGED TO THE POLYMERIZATION REACTOR, WITH SMALL AMOUNTS OF THE CATALYST USED FOR THE POLYMERIZATION OF ETHYLENE, WHILE CAREFULLY EXCLUDING MOISTURE, AND SEPARATING THEM FROM THE PRECIPITATE FORMED. 